Stock-Based Compensation - Summary of Stock-Based Compensation Expense by Type (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Stock Based Compensation [Line Items]
Total	$ 2,479	$ 4,133
Service-based Awards [Member]
Stock Based Compensation [Line Items]
Total	1,803	1,963
Director Awards [Member]
Stock Based Compensation [Line Items]
Total	402	402
Performance-based Awards - Long-term Incentive Plan [Member]
Stock Based Compensation [Line Items]
Total	28	226
Performance-based Awards - Short-term Incentive Plan [Member]
Stock Based Compensation [Line Items]
Total	0	1,335
Employee Stock Purchase Plan [Member]
Stock Based Compensation [Line Items]
Total	245	205
Stock Options [Member]
Stock Based Compensation [Line Items]
Total	$ 1	$ 2